Forget the rules and regulations, let's sit in a hangar and talk. How many pilots would descend in an area they didn't know, where they fully expected to see a mountain close by but couldn't, if they absolutely didn't need to?
The PIC had a mindset and didn't adjust his thinking as circumstances changed. Even when he descended and still couldn't see the mountain he didn't sense the danger (FE did). He relied totally on instruments but was flying VFR.
Was the flight doomed when it left NZ? Most pilots wouldn't have done what Collins did, I hope, even those who "feel" he was blameless.
The PIC was put in a bad place by others but he stuffed up too. Would have helped if he'd done some navigation on the way down: AINS output on chart.
Remember the dead, yes, make excuses for human frailty, yes, but starting another argument you can't win?